One of vehicle door lock devices includes an open mechanism adapted to be actuated in such a manner that a vehicle door is openable relative to a vehicle body, a lock mechanism provided with an active lever capable of driving a lock/unlock member (open link) placed in the open mechanism at a locking position (lock position) or an unlocking position (unlock position), the lock mechanism for restraining or permitting an action of the open mechanism so as to lock or unlock the door, an electric actuator for driving the lock/unlock member (open link) at the locking position (lock position) or the unlocking position (unlock position) through the active lever, and a housing accommodating the open mechanism, the lock mechanism, and the electric actuator. Such a device is shown in Japanese Patent Application Publication No. 2006-266026, for example.
In the vehicle door lock device described in the above patent document, as shown in FIG. 6, an electric actuator 3 for driving an open link 2 (lock/unlock member) at a locking position (lock position) or an unlocking position (unlock position shown in FIG. 6) through an active lever 1 (lock lever in the above patent document) is provided with an electric motor 3a driven in accordance with a lock operation and an unlock operation, a worm 3b provided integrally with an output shaft of the electric motor 3a, the worm being rotated and driven by the electric motor 3a, and a worm wheel 3c having a pair of engagement projections 3c1, 3c2 linked with the active lever 1 to be meshed with the worm 3b. The pair of engagement projections 3c1, 3c2 is provided on a side surface of the worm wheel 3c and selectively engageable with a concave portion 1a provided in the active lever 1.
In the electric actuator 3 shown in FIG. 6, the electric motor 3a rotates and drives the worm 3b, so that the worm wheel 3c is rotated and driven. By rotation of the worm wheel 3c, the pair of engagement projections 3c1, 3c2 is selectively engaged with the concave portion 1a provided in the active lever 1, so that the active lever 1 is actuated and the open link 2 is driven at the unlocking position (unlock position) shown in FIG. 6 or the locking position (lock position) (not shown).